Yin Chun-Hao, Li Pei-Xin, Hou Lei-Tian, Xu Zhen-Kun, Wu Cai-Ping, Li Shao-Bo. Study on the excited states of zinc porphyrinogen and anisotropy of 2, 2, 6, 6-tetramethylpiperidinooxy by the technology of electron paramagnetic resonanceJ. Acta Physica Sinica, 2014, 63(9): 097201. DOI: 10.7498/aps.63.097201